Conventional automatically operating valves substantially comprise valves which are operated by solenoid drivers and valves which are operated by power-operated motors.
Upon receiving a drive signal or a drive output from a sensor or an operating switch, the valve body of such valve is moved by the solenoid driver or the power-operated motor toward or away from the valve seat to automatically close or open the valve.
The actuator of the conventional operating valves, however, is either made of the solenoid driver or the power-operated motor so that high resolution cannot be achieved with respect to the movement of the valve body of such conventional actuator, whereby, the valve cannot accurately control the water flow although the simple opening or closing of the valve can be achieved.
Especially, the application of such an automatically operating valve to a mixing valve for producing water of a desired temperature is almost impossible or extremely difficult since it requires an extremely fine regulation of the movement of the valve body to mix hot water and cold water to obtain the water of a desired temperature.
Accordingly, it is an object of the present invention to provide an automatically operating valve which can resolve the above drawbacks of the conventional valves by utilizing piezoelectric actuators as the drive means of the valve, wherein these piezoelectric actuators can finely regulate the opening rate or angle of the valve whereby the water flow can be accurately adjusted.
It is another object of the present invention to provide a mixing valve provided with piezoelectric actuators which can finely and accurately adjust the mixing ratio of hot water with cold water to produce a water of a desired temperature.
It is still another object of the present invention to provide an automatically operating valve provided with piezoelectric actuators which can be assembled in a compact form and can be mounted readily and easily on any place.
It is a further object of the present invention to provide an automatically operating valve provided with piezoelectric actuators which can completely close the valve by automatically or manually moving the valve body toward the valve seat in case of emergency such as at the time of a power failure or cutting off of the electricity, whereby the leakage of water can be prevented, thereby enabling the saving of water.
It is a still further object of the present invention to provide an automatically operating valve provided with piezoelectric actuators which can completely close the valve by automatically moving the valve body utilizing the biasing force of the spring and deenergizing the clamping piezoelectric elements in case of emergency such as at the time of water-stoppage-mode operation power, whereby the leakage of water can be prevented, thereby enabling the saving of water.
It is even a still further object of the present invention to provide an automatically operating valve provided with piezoelectric actuators, wherein the front tip of the plunger is formed as a separate element from the plunger and is biased by a spring to apply a biasing force to the valve body, whereby even when an impulse water pressure is generated in the water passage, only the front tip of the plunger is moved backward so that the position of piezoelectric elements relative to the plunger can be held unchanged, thereby the fine adjustment of the water flow can be acheived throughout the flow regulating operation.
It is even a still further object of the present invention to provide an automatically operating valve provided with piezoelectric actuators, wherein the front tip of the plunger is constricted to have a diameter smaller than the remaining part of the plunger, whereby the water pressure which the plunger receives on the tip end of the plunger can be minimized and the plunger can be extended or retracted accurately by the actuation of the piezoelectric elements resulting in the fine adjustment of the water flow.
It is even a still further object of the present invention to provide a faucet which compactly incorporates a mixing valve provided with piezoelectric actuators therein so that the faucet can be compactly mounted on any part of the washroom whereby the remaining space of the washroom can be efficiently utilized.
In summary, the present invention discloses an automatically operating valve for regulating water flow comprising a casing, an inflow passage formed in one side of the casing, an outflow passage formed in the other side of the casing, a valve seat formed in a communicating passage which connects the inflow passage and the outflow passage, a valve body retractably mounted on the valve seat and a piezoelectric actuator for moving the valve body towards and away from the valve seat.
The present invention also discloses a mixing valve for mixing hot water with cold water to produce water of a desired temperature comprising a casing, a cold water inflow passage and hot water inflow passage formed in one side of the casing, a mixture outflow passage formed in the other side of the casing, a valve seat formed in a communicating passage which connects the inflow passage and the outflow passage, valve bodies retractably mounted on the valve seats and piezoelectric actuators for moving the valve bodies towards and away from the valve seats.
The present invention also discloses a faucet provided with the above-mentioned mixing valve at the proximal end thereof for enabling the fine flow control and the fine temperature control of the water tapped from the outlet of the faucet.